Xtium2-CXP PX8 User's Manual
Xtium2-CXP PX8 Reference
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Flat Field Correction: Theory of Operation
The following provides additional details on the Flat Field Correction and Flat Line Correction
(FFC/FLC) implementation.
Flat Field Correction Lists
The Xtium2-CXP PX8 supports defining more than one Flat Field Correction (FFC) / Flat Line
Correction (FLC) data sets. Using the Xfer parameter CORXFER_PRM_FLATFIELD_CYCLE_MODE,
the user can decide to cycle automatically through the list of FFC/FLC sets by setting the parameter
to CORXFER_VAL_FLATFIELD_CYCLE_MODE_AUTOMATIC, or select a specific FFC/FLC set from the
list by setting the parameter to CORXFER_VAL_FLATFIELD_CYCLE_MODE_OFF and selecting the
FFC/FLC index to use with the parameter CORACQ_PRM_FLAT_FIELD_SELECT.
While the cycling mode is set to off, users can upload new coefficients to an inactive FFC set even
when grabbing. When cycling automatically, the FFC/FLC sets are selected in a round-robin fashion,
changing at the beginning of every new frame.
The architecture of the Xtium2-CXP PX8 is such that the FFC/FLC data sets are independent of the
host buffers. In automatic mode, the FFC/FLC sets are chosen in a round-robin fashion as images
are acquired. So if using the Xfer cycling mode Synchrounous with Trash, it is recommended that
the number of host buffers be a multiple of the number of FFC/FLC in the list in order to maintain
the FFC/FLC relationship with the Host buffers.
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When the FFC/FLC cycle mode automatic is active, reset the acquisition module to start on the
1
st
FFC/FLC data set of the selected list as follows:
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Disconnect/Reconnect the transfer (assuming 1
st
buffer is empty).
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Selecting a set using the CORACQ_PRM_FLAT_FIELD_SET_SELECT parameter will choose
the 1
st
FFC/FLC in the list of the selected set.
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When the FFC/FLC cycle mode automatic is active, start the acquisition module to start on a
specific FFC/FLC of the selected list as follows:
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While acquisition is stopped, by selecting an Xfer pair [ACQ, Buffer]. The index of the
FFC/FLC will be selected based on the modulo of the number of FFC/FLC in the list with
respect to the [ACQ, Buffer] index pair.
Flat Field Correction Sets
The concept of sets allows a user to define multiple lists of FFC/FLC correction data. The FFC/FLC
API allows users to allocate and pre-program those FFC/FLC sets. When acquiring images, the
board driver will cycle through the FFC/FLC list of the selected set. During that operation, users can
upload new FFC/FLC data to non-active sets without any ill effects.
When changing the active set while grabbing, the new active set will be switched when the current
cycling of the current list is completed.
Xtium2-CXP PX8 specific limitations
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Software driver permits the creation of up to 16 FFC/FLC sets.
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Software driver permits the use of up to 16 sets.
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When the FFC cycling mode is off, the concept of sets is not used. Whichever a FFC index is
chosen using CORACQ_PRM_FLAT_FIELD_SELECT, it will be used independently of the set it
belongs to.
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Upload of any FFC data is permitted at any time, even while grabbing. If an upload is done to
an FFC index of the currently select set while grabbing, then the resulting acquired image will
be undefined.
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When changing FFC cycling mode, the acquisition must be stopped.
